Activated persulfate by DBD plasma and activated carbon for the degradation of acid orange II

In this study, the effect of activated peroxydisulfate (PDS) by dielectric barrier discharge (DBD) plasma and activated carbon (HGAC) on the removal of acid orange II (AOII) was investigated. The effects of applied voltage, PDS dosage, HGAC dosage, initial pH value, and inorganic anions on the removal rate of AOII were discussed. The main free radicals degrading azo dyes during the experiment were also studied. Experimental results show that the removal rate of AOII in DBD/HGAC/PDS synergistic system is much higher than that in the single system. With the applied voltage of 16 kV, HGAC dosage of 1 g l⁻¹, PDS and AOII molar ratio of 200:1, initial pH value of 5.4 and concentration of AOII solution of 20 mg l⁻¹, the removal rate of AOII reached 97.6% in DBD/HGAC/PDS process after 28 min of reaction. Acidic and neutral conditions are beneficial for AOII removal. Sulfate and hydroxyl radicals play an important role in the removal of AOII. Inorganic anions are not conducive to the removal of AOII.